Cloud seeding with dry ice is used to create rain! Cloud seeding was discovered accidentally in a General Electric laboratory in New York. Below are several interesting cases in which cloud seeding was used:
In 1946, GE chemist Vincent Schaefer caused a snowfall near Schenectady, NY by dumping six pounds of dry ice from an airplane.
Cloud seeding was used by the U.S. Air Force in Vietnam to extend the monsoon season.
The radioactive fallout from the Chernobyl nuclear disaster in Russia was contained and kept from reaching Moscow with cloud seeding.
Cloud seeding was used in China to reduce air pollution during the 2008 Olympic Games, and it is still used in airports to remove fog.